Positioning fixture to facilitate nozzle drilling by edm

ABSTRACT

Fixture assembly for holding a nozzle blank on which spray openings are to be formed by electric-discharge machining. The fixture assembly comprises a base, a gage block, a pivot block, an adapter block, an adapter, and a headblock. The nozzle blank is held between the adapter and a conical recess in the headblock. The headblock is adjustably positioned so as to accommodate nozzle blanks of different sizes. The adapter is selected so as to give the desired angle between the nozzle blank axis and the axis of the imaginary cone on which the spray openings are to be formed. The gage block determines the angle at which the pivot block is held and thus the angle of the cone of the spray openings.

United States Patent Inventors Appl. No. Filed Patented AssigneePOSITIONING FIXTURE T FACILITATE NOZZLE DRILLING BY EDM I Claims,Drawing Figs.

u.s. Cl 219/69 R, 77/64 rm. 0 B23b 1/12, B23b 47/23 Field ol Search77/64; 219/69 E, 69 M, 69 R [56] References Cited UNITED STATES PATENTS3,098,148 7/1963 Piot et a1 219/69E 3,350,963 11/1967 Roosa 77/64XPrimary Examiner-Ralph F. Staubly Attorney-Floyd B. Harman ABSTRACT:Fixture assembly for holding a nozzle blank on which spray openings areto be formed by electric-discharge machining. The fixture assemblycomprises a base. a gage block, a pivot block, an adapter block, anadapter, and a headblock. The nozzle blank is held between the adapterand a conical recess in the headblock. The headblock is adjustablypositioned so as to accommodate nozzle blanks of different sizes. Theadapter is selected so as to give the desired angle between the nozzleblank axis and the axis of the imaginary cone on which the sprayopenings are to be formed. The gage block determines the angle at whichthe pivot block is held and thus the angle of the cone of the sprayopenings.

POSITIONING FIXTURE TO FACILITATE NOZZLE DRILLING BY EDM This inventionrelates to a fixture assembly for holding a blank on which machiningoperations are to be performed. More specifically, the invention relatesto a fixture assembly for holding nozzle blanks in which spray openingsare to be formed. i

It is known to inject fuel in the form of an atomized spray in anengine, by means of a nozzle and a rapidly reciprocating valve rod inthe nozzle tip. The fuel is sprayed into the engine through a pluralityof spray openings in a spherical tip end of the nozzle, which openingsare distributed about an imaginary cone whose tip coincides with thecenter of the spherical end and whose axis may coincide with that of thenozzle or be at an angle thereto. Since the spray openings and thespherical end of the nozzle are small, it is desirable to use a wireelectrode and form the openings by electric-discharge machining.

The fixture assembly of the present invention holds the nozzle adjacentthe wire electrode for the forming of spray openings. The assembly isconstructed to handle a plurality of variables with particular means:various sizes of the spherical end of the nozzle, by means of a headblock screw head; various cone angles of the cone on which the sprayopenings are arranged, by means of a gage block; various angles betweenthe cone axis and the nozzle axis, by means of a selected adapter; andvarious numbers of spray openings, by means of a selected indexingplate.

It can be appreciated from the foregoing that nozzle orifices can belocated accurately by setting any combination of angles in the threeplanes of the indexing plate, gage block, and adapter. Thus, oneindexing plate if substituted for another can change machining of anozzle blank so that each orifice makes an angle to the adjacent orificewhich is smaller, for example, thereby increasing the total number ofspray openings Thus, one of the gage block steps if substituted foranother can change the angular extent or circumferential length of thering of orifices in a nozzle blank so that the cone at its apex changesto an angle which is smaller, for example. Thus, one adapter ifsubstituted for another adapter can change the axis of the cone or ofthe ring of nozzle openings in a nozzle blank so that the angle betweenthe cone axis and nozzle axis is changed to a smaller angle, forexample, enabling the spray pattern to proceed more nearlylongitudinally from the nozzle rather than to one side.

An orifice so set is accurately located and separately set for any anglewithin three planes relative to the nozzle valve axis. The importantfeature is that variables in each plane are independent of the othertwo.

More specifically, a fixture provided according to our invention forvertical drilling of a hole pattern in a nozzle comprises: a rotatableadapter block; a pivot block with rotatable mounting means rotatablysupporting the adapter block thereon, and supported by tiltable mountingmeans to tilt the two blocks from a horizontal position about a fixed,horizontal pivot axis of the pivot block; and nozzle mounting means forsupporting a nozzle to be drilled and supported on the adapter block;the rotatable mounting means being effective to rotate the adapter blockin the pivot block for positioning the nozzle for drilling a ring ofholes a plurality of which are equiangularly spaced apart; the tiltablemounting means comprising the preceding discussed gage block engageableat a point on the pivot block to set the tilt angle by setting theheight of the pivot block at that point; the nozzle mounting meanscomprising the preceding discussed adapter which is revolved by theadapter block, as the adapter block rotates, to carry the nozzle intopositions for drilling as described. In particular, the rotary mountingmeans is the preceding discussed indexing plate selectable fromsubstitutable rotary indexing plates each with a different number ofindexed positions to afford precisely that number of holes per ring. Thegage block of the tiltable mounting means is a spacer selected fromsubstitutable gage block portions each of a different heightdeterminative of a precise spacing. The adapter is selected fromsubstitutable adapters for holding nozzles each forming a differentangle to the adapter block, determinative of the precise angle of thecone pattern axis to the nozzle.

In the drawing:

FIG. 1 is an end view of a nozzle;

FIG. 2 is a longitudinal sectional view of the nozzle taken on the line2-2 of FIG. I;

FIG. 3 is an elevational view of fixture assembly of the presentinvention;

FIG. 4 is an end view of one end of the fixture assembly;

FIG. 5 is an end view of the other end of the fixture assembly;

FIG. 6 is a plan view of the fixture assembly:

FIG. 7 is an elevational view of a headblock forming part of the presentfixture assembly;

FIG. 8 is an end view of the headblock;

FIG. 9 is an enlarged fragmentary elevational view of the headblock;

FIG. 10 is an enlarged fragmentary sectional view taken on the line10-10 of FIG. 9;

FIG. 11 is a fragmentary enlarged plan view of the portion of FIG. 6contained in the enclosure 11 end showing the engagement of the end of anozzle blank with the headblock;

FIG. 12 is a longitudinal sectional view taken on the line 12--l2 ofFIG. 14 and showing a pivot block of the fixture as sembly;

FIG. 13 is an end view of the pivot block taken from one end;

FIG. 14 is an end view of the pivot block taken from the other end;

FIG. 15 is a fragmentary sectional view taken on the line 15-45 of FIG.14;

FIG. 16 is an elevational view of an adapter block of the fixtureassembly;

FIG. 18 is an end view of an adapter of the fixture assembly; FIG. 17 isan end view of the adapter block;

FIG. 19 is a longitudinal sectional view taken on the line l9--19 ofFIG. 18; and

FIG. 20 is a fragmentary end view of the adapter taken on the line 20-20of FIG. 19.

The reference character 30 designates a nozzle or nozzle blank,depending on whether certain spray openings have or have not been formedtherein. The fixture assembly of the present invention is adapted tohold the nozzle blank 30 while spray openings are formed therein byelectric-discharge machining.

As shown in FIG. 2, the nozzle 30 has a central bore composed of regions31 and 32. An elongated plunger or rod 34, which is positioned in thenozzle 30, has a long portion 35 fitting the bore region 31 of thenozzle 30, a long portion 36 lying within the bore region 32 in radiallyspaced relation thereto, and a conical tip 37 beyond the portion 36seated on a conical seat 38 in the nozzle 30. Beyond the conical seat38, the nozzle 30 has a spherical end 39 provided with a plurality ofspray openings 40. The nozzle 30 has two longitudinal openings 41 whichconnect an internal peripheral groove 41a between the bore regions 31and 32 with an external annular groove 42 formed in the end of thenozzle remote from the spherical end 39. The groove 41a communicateswith a long annular space formed between portion 36 of plunger 34 andbore region 32 of nozzle 30. The nozzle 30 and plunger 34 may be usedfor injection of liquid fuel into a diesel engine. The liquid fuel isapplied to the nozzle 30 by way of the annular groove 42 and thelongitudinal passages 41 and causes the plunger 34 to lift because of aspring (not shown) holding conical end 37 on the plunger 34 against theconical seat 38 in the nozzle 30 and a stop (not shown) allowing onlyvery limited movement of the plunger 34 to the left as viewed in FIG. 2.As a result of the opening the fuel passes between the conical end 37and the seat 38 and is sprayed out the openings 40 into the engine.

For various reasons having to dow with engine operation, the sprayopenings 40 which may, for example, be from 4 to in number, have theiraxes arranged on and distributed about an imaginary cone. This imaginarycone has an apex angle represented by G and an axis an angle F with theaxis of the nozzle or nozzle blank (FIG. 2). The purpose of the fixtureassembly of the present invention is to hold the nozzle blank 30 so thatspray openings may be formed therein by electric-discharge machiningwith various numbers of spray openings, various conical angles G, andvarious angles F between the axis of the nozzle blank 30 and thespray-cone axis. The fixtures assembly accommodates nozzle blanks 30with spherical ends 39 of various radii.

As shown in FIGS. 3-6, the fixture assembly comprises a base 43, a gageblock 44, a pivot block 45, an adapter block 46, an adapter 47, and ahead block 48. The gage block 44, which is slidably positioned on afloor 49 of the base 43, has a plurality of steps 50 of different levelsengageable with a roller 51 fixed to the pivot block 45 so that thepivot block 45 will assume various angles with respect to base 43 abouta horizontal axis 52. Axis 52 is formed by virtue of the support of thepivot block 45 on and between upstanding ears 53 of the base 43 throughpins 54 which enter the pivot block 45 and ears 53 on the horizontalaxis 52. The spray-cone angle G, shown in FIG. 2, is determined by theangle of the pivot block 45 about axis 52, as will be explained morefully presently.

As shown in FIG. 11, the head block 48 has a conical recess 55 whichengages the spherical end 39 on the nozzle blank 30 when the latter ispositioned in the fixture assembly. The head block 48 is adjustablymounted on the pivot block 45, adjustment of the position of the headblock 48 adapting it to spherical ends 39 of various radii, as willpresently be explained in greater detail. The adapter 47 (FIGS. 3 and 5)is detachable connected with the adapter block 46 so as to be angularlymovable therewith about an axis 56 (FIG. 8) and supports the end of thenozzle blank 30 remote from the spherical ends 39 on an axis 57 whichforms an angle with the axis 56 which is equal to and determinative ofangle F between the nozzle axis and the spray-cone axis, all as will bepresently explained in greater detail.

The reference character 58 designates a machining or forming axis, whichis vertical, perpendicular to the horizontal axis 52, and lying in thesame plane as the axis 56. The axes 52, 56, and 58 intersect at a commonpoint. A wire electrode (not shown) for forming the spray openings 40 byelectricdischarge machining, moves along the machining axis 58 and isheld in a slide and wire guide 59 (FIG. 3).

As shown in FIG. 12, the pivot block 45 has at one end spaced ears 60provided with circular openings 61 for receiving the pivot pins 54 (FIG.3). The pivot block 45 has, as shown in FIGS. 12 and 14, a circularcylindrical opening 62 formed in a portion 63 of the pivot block 45extending from the end thereof opposite the cars 60 to a mid region. Theopening 62 has as its axis the axis 56 (FIG. 3) and is adapted toreceive the adapter block 46 (FIG. 3). A recess 64 is formed in thepivot block 45 in the portion 63 below the opening 62 at the end of thepivot block 45 away from the ears 60 and is adapted to receive and besecured to the cylinder 51 (FIG. 3). As shown in FIGS. 12 and 14, thepivot block 45 has a transverse slot 65 formed in the portion 63 incommunication with the opening 62. A threaded opening 66 is formedacross one end of the slot 65 in an upper corner of the portion 63. Asshown in FIGS. I4 and I5, a longitudinal opening 67 extends through theportion 63 of the pivot block 45 at an upper comer thereof opposite thethreaded opening 66, a slot 68 is formed in the top of the opening 67.One end of the opening 67 is closed by a disc 69. The purpose of thetransverse slot 65. The threaded opening 66, and the opening 67 willappear presently.

As shown in FIGS. 12 and 13, the pivot block 45 is provided with twolongitudinal openings 70 extending from the end of the pivot block 45where the ears 60 are located to an intermediate region of the pivotblock. The openings 70 are at opposite sides of the pivot block 45nearthe base thereof. Inward of the openings 70, there are two longitudinalopenings 71,

which are smaller in diameter than the openings 70, but like theopenings 70 extend from the same end of the pivot block 45 to anintermediate region thereof. An opening 72 is provided near the innerblind end. The opening 72 extends vertically from the base of the pivotblock 45 across the opening 71 to the opening 62. The purpose of theopenings 70, 71, and 72 will appear presently.

As shown in FIGS. 7 to 11, the conical recess 55 is fonned in theheadblock 48 near and at its top. The pivot block has a narrowtransverse horizontal surface 73 at the top, which is defined by anintermediate vertical surface 74 and a sloping surface 75. The conicalrecess 55 is formed so as to extend from the vertical surface 74 and tointersect the top horizontal surface 73 so as to form therein an opening76, through which the wire electrode (not shown) has access to thespherical end 39 of the nozzle blank 30. A cylindrical bore 760 extendsfrom the conical recess 55 into the sloping surface 75 of the head block48. The bore 76a was originally formed between the surface 74 and 75before the conical recess 55 and serves as an aid in forming the same.

The surface 75 on the headblock 48 is made to slope downwardly and tothe right as viewed in FIGS. 3, 8, and 10 from the narrow top surface73, so that there will be no interference between the head block 48 andthe slide and wire guide 59 when the head block 48 and the pivot block45 are swung counterclockwise as viewed in FIG. 3 to an appreciableextent and the guide 59 along with the wire electrode is moveddownwards.

The head block 48 has two large openings 77 and two small openings 78which are, respectively, of the same diameter as the openings 70 and 71in the pivot block 45 (FIGS. 12 and 13). When the pivot block 45 andhead block 48 are in the assembled position of FIGS. 3, 5, and 6, theopenings 77 and the openings 78, respectively, are aligned with theopenings 70 and 71. In the assembled position, guide pins 79 (FIGS. 5and I 6) in the openings 70 (FIGS. 12 and 13) in the pivot block 45 fitthe openings 77 (FIG. 7) in the head block 48 for mounting the headblock 48 on the pivot block 45. The head The head block 48 is heldagainst the pivot block 45 by a pair of springs 80 (FIG. 6) which arepositioned in openings 71 (FIG. 12) in pivot block 45 and openings 78(FIG. 7) in head block 48 and are connected to the pivot block 45 andthe head block 48 by pins 81 (FIG. 6) which engage the ends of thesprings 80 (FIG 6) and are lodged in vertical openings 72 (FIG. I2) inpivot block 45 and vertical openings 82 (FIG. 7) extending in theheadblock 48 from the base thereof across the openings 78.

As shown in FIGS. 3 and 5, an adjusting screw 83 with a large disklikehead 84 extends through the head block 48 in threaded engagementtherewith and abuts the end of the pivot block 45. The screw head 84 hasmarkings 85 representative of radii of the spherical end 39 on thenozzle blank 30 (FIG. 2), which markings are to be used in conjunctionwith a marking 86 on the head block 48. The adjusting screw 84 may beheld against rotation by a set screw 87 which engages a threaded openingin the head 84 and abuts the headblock 48.

As shown in FIG. 16 and 17, the adapter block 46 has a circularcylindrical exterior 88 which is adapted to fit opening 62 in the pivotblock (FIG. 12). The adapter block 46 has a peripheral groove 89 whichis to cooperate with the transverse slot 65 FIGS. 12 and 14) in thepivot block 45 and with a narrow bar 90 FIGS. 3 and 6) positioned in theslot 65 and the peripheral groove 89, in holding the adapter block 46against movement with respect to the pivot block 45 along the axis 56while allowing angular movement of the adapter block about the axis 56.The adapter block 46 is released from the pivot block 45 when the bar 90is swung out of the peripheral groove 89 in the adapter block 46 (FIG.16) about a screw 91 FIG. 6) engaging the opening 66 in the pivot block45 (FIGS. 12 and 14). The narrow bar 90 is manipulated by a screw 92(FIGS. 3 and 6) which protrudes from the narrow bar at the ends thereofremote from the screw 91.

As shown in FIG. 16, the adapter block 46 has a short axial extension 93and a threaded axial opening 94 formed thereat which are employed tomount an index plate 95 (FIGS. 3, 4, and 6) on the end of the adapterblock 46 beyond the pivot block 45 by means of a screw 96. As shown inFIGS. 3 and 4, the index plate 95 is connected to the adapter block 46for rotation therewith by a pin 97 extending through the index plateinto the adapter block. The index plate 95 extends radially outwardly ofthe adapter block 46 so as to overlap the portion 63 thereof in whichopening 62 is formed and has at this radially outward location aplurality of peripherally distributed equally spaced openings 98corresponding in number to the spray openings 40 (FIG. 2) to be formedin the nozzle blank 30. The index plate 95 and the adapter block 46 arefixed at various angular positions of the adapter block with respect tothe pivot block 45 about the axis 56 by means of the openings 98 and areduced projection 99 receivable in the openings, which projection, asshown in FIG. 6, is formed on one end of a retractable member 100slidably positioned in the opening 67 (FIG. in the adapter block 46. Themember 100 is urged toward the index plate 95 by a spring 101 (FIG. 6)one end of which acts against the end of a long recess formed from theend of the member 100 opposite the projection 99 and the disc 69 (FIG.15) fixed in the end of the opening 67. The retraction of the projection99 from the openings 98 in the index plate 95 is effected bymanipulation of a screw I02 (FIGS. 4 and 6) attached to the retractablemember 100 and projecting therefrom through the opening 68 (FIG. 15) inthe pivot block 45 to the exterior thereof.

As shown in FIGS. 16 and 17, the adapter block 46 has at the end remotefrom the extension 93 by which the index plate 95 is attached, arelatively wide transverse groove 103, which is adapted to receive theadapter 47 (FIGS. 18 and 19). The adapter block 46 has an axial opening104 at the base of the groove 103, which opening cooperates with theopening 105 (FIG. 19) in the adapter 47 and with a dowel 106 (FIG. 3)received in the openings 103 and 104 to position the adapter 47 in thegroove 103 in the adapter block 46. A screw 107 (FIG. 3) extendingthrough an opening 108 (FIG. 19) in the adapter 47 into threadedengagement with an opening 109 (FIGS. 16 and 17) in the adapter block 46secures the adapter 47 to the adapter block 46, as shown in FIGS. 3 and6.

As shown in FIGS. 18 and 19, the adapter 47 has an end portion 110 whichis thicker than the balance of the adapter and has an inclined surface111 which is perpendicular to the axis 57 (FIG. 3) along which thenozzle blank 30 extends when in the present fixture assembly. Arelatively large shallow circular recess 112 is formed in the surface111. A relatively small deep circular recess 113 is formed in the baseof the recess 112. The axes of the recesses 112 and 113 are coincidentwith the axis 57, and the bases at these recesses are perpendicular toaxis 57 and parallel to surface 111. As shown in FIG. 20, two recesses114 are formed in the base of the recess I12 radially outwardly of therecess 113, with an angular spacing from one another about the axis 57,of some substantial angle other than 180, for example 135. The spacingof the openings 114 in the adapter 47 is the same as that of recesses115 (FIGS. 1 and 2) formed in the nozzle blank 30 at the peripheralgroove 32. Dowels 116 (FIG. 3) are received in the recesses 114 and 115of the adapter 47 and the nozzle blank 30 for properly orienting thenozzle blank about the axis 57.

As shown in FIG. 3, a spring 117 acts between the adapter 47 and the endof the nozzle blank 30 away from the spherical end 39 thereof to urgethe spherical end 39 against the conical recess 55 in the head block 48The end of the nozzle blank 30 is received in the recess 112 (FIG. 19)in adapter 47, and the spring 117, in recess 113 (FIG. 19) therein.

SIMPLEST CONE APEX ANGLE-4N GENERAL all drilling is perpendicular to andintersects the vertical forming axis 58.

SIMPLEST CONE APEX ANGLE-WITH SIMPLEST CONE AXIS ANGLE The simplest coneaxis angle imparted to a hole pattern in the nozzle is a 0 angle, i.e.,the cone axis and nozzle axis coincide.

The nozzle and the pivot block are horizontal, and their axes arecoincident and their axes are perpendicular to and intersect thevertical forming axis 58.

Each hole in the nozzle is therefore at right angles to the nozzle axis.Although FIG. 2 does not show each hole at right angles to the nozzleaxis, the result can be appreciated by visualizing the cone apex angle Gincreased to 180 and visualizing the cone axis angle F decreased to 0.

FIXTURE ADJUSTMENT When the fixture assembly of the present invention isto be used for forming spray openings 40 in the nozzle blank 30, thefirst step is to adjust the head block 48 in accordance with the radiusof the spherical end 39 on the nozzle blank 30 in which the openings 40are to be formed. The apex of the imaginary conical surface on which thespray openings 40 lie should coincide with the center of curvature ofthe spherical end 39. For this to occur, the center of curvature shouldbe on the machining axis 58, along which the wire electrode moves. Theheadblock 48 is adjusted by the screw 83, which is turned to bring theparticular marking on screw head 84 corresponding to the desired radiusof the spherical end 39 opposite the marking 86 on the headblock 48, asshown in FIG. 5. In the position of FIG. 5, the screw 83 is set for aradius of 1.2 mm., the minimum radius shown by markings 85.Correspondingly, in the position of FIG. 3, head block 48 abuts pivotblock 45, because the end of screw 83 does not protrude from the headblock 48. Thus, headblock 48 is as far to the left as possible as viewedin FIG. 3, with respect to pivot block 45, and conical recess 55 is asfar to the left as possible as viewed in FIG. 11, with respect tomachining axis 58, and so can engage spherical end 39 of minimum radiuson nozzle blank 30 so as to place the center of curvature of thespherical end on the machining axis 58.

As the adjusting screw 83 is adjusted from the position of FIGS. 3 and5, the end of the screw protrudes against the adjacent end of the pivotblock 45, and so the headblock 48 moves rightwards as viewed in FIG. 3,with respect to the pivot block 45. As the headblock 48 moves to theright, the conical recess 55 also moves rightwards as viewed in FIG. 11,with respect to the machining axis 58 and becomes suited to engaging aspherical end 39 of greater radius for placing the center of curvaturethereof on the machining axis 58 for proper location of the sprayopenings 40. The farther the end of screw 83 protrudes from headblock48, the greater the spacing of headblock 48 from pivot block 45, thefarther to the right as viewed in FIG. 11 the conical recess 5 withreference to machining axis 58, and the greater the radius of sphericalend 39 to be accommodated in conical recess 55. Once the adjusting screw83 is properly positioned to give the correct location of the conicalrecess 55, the adjusting screw is fixed by the set screw 87.

Now, the narrow bar is swung about the screw 91 out of thecircumferential groove 89 in the adapter block 46, whereby the adapterblock and the attached adapter 47 can be shifted to the left tofacilitate insertion of the nozzle blank 30 in the fixture assembly. Itis presumed that the correct adapter 47 has been chosen to give thedesired angle F (FIG. 2) between nozzle-blank axis and spray-cone axis,which is equal to the angle between the axes 56 and 57 (FIG. 3). Withthe placing of the nozzle blank 30 on the adapter 47, the dowels 116will have been received in the recesses in the blank 30 and the adapter4'7 and the spring 117 will have been applied between the end of thenozzle blank 30 and the adapter 47.

Now the adapter block 46 is moved to the right as viewed in FIG. 3 sothat the peripheral groove 89 in the adapter block 46 registers with theslot 65 in the pivot block 45, whereupon the narrow bar 90 is swungdownwards into engagement with the peripheral groove 89. It is presumedthat the index plate 95 with the correct number of opening 98 thereinfor the desired number of spray openings 40 to be formed in the nozzleblank 30 has been attached to the adapter block 46 by the screw 96 andthe pin 97. The gage block 44 is suitably positioned with respect to theroller 51 on the pivot block 45 so that the roller rests at step 50 onthe gage block 44 for the desired spraycone angle G (FIG. 2).

I80 CONE APEX ANGI..E-SPECIFIC EXAMPLE As positioned in FIG. 3, the gageblock 44 holds the pivot block 45 at the angle required for a spray-coneapex angle G of 180 to be formed. With the spray-cone angle of 180, theopenings 40 to be formed will, in a sense, not be on a cone, but on aplane.

DRILLING Now, the wire electrode is brought down along the forming axis58 to form the first of the openings 40 in the spherical end 39 of thenozzle blank 30. After the first opening is formed and the wireelectrode is returned upwardly, the reduced projection 99 is retractedfrom the associated opening 98 in the index plate 95 by manipulation ofthe screw 102 along the slot 68 in the pivot block 45. The index plate95, adapter block 46, and adapter 47 are angularly shifted to bring thenext opening 98 to the projection 99, whereupon the screw 102 isreleased and the spring 101 acts against the retractable member 100 toengage the projection 99 with the groove opening 98. The shifting of theprojection 99 (FIG. 6) from the first opening 98 to the next opening 98produces a needed shifting of the nozzle blank 30 about the axis 56 toposition the spherical end 39 on the nozzle blank so that the wireelectrode descending again along the forming axis 58 will form a secondspray opening 40 at the desired location appropriately displaced fromthe first opening 40. The procedure is repeated until an entire set ofspray openings 40 is formed.

I70 CONE APEX ANGLE-SPECIFIC EXAMPLE If on the new nozzle 30 openingsare to be formed on a smaller cone angle G (FIG. 2), the gage block 44is moved to the right as viewed in FIG. 3, resulting in counterclockwiseswinging of pivot block 45 due to engagement of the cylinder 51 with alower step 50 on the gage block 44. This means an increase in the anglebetween the machining axis 58 and the axis 56 of the pivot block 45.When in the position of FIG. 3, the cone angle is 180, the angle betweenthe axes 56 and 58 is 90. When the cylinder 51 is shifted to 170 of thegage block 44, the angle between the axes 56 and 58 is increased by Thecone angle G is equal to twice the difference between 180 and the anglebetween the axes 56 and 58. The angle between the nozzle blank axis andthe spray-cone axis is the angle between the axes 56 and 57 of the pivotblock 45 and the nozzle blank 30 when in the fixture assembly.

CONE AXIS ANGLE-SPECIFIC EXAMPLE The angle of the axis 57 with respectto the axis 56 is deter mined by the appropriate selection of theadapter 47. In FIG. 3, the adapter 47 shown provides an angle of 15between the axes 56 and 57.

It is contemplated that other adapters 47 providing angles of 0 and mayalso be used. The index plate 95 shown in FIG. 4 has eight openings 98,enabling eight spray openings 40 to be formed in the nozzle blank 30. Ifother members of spray openings are to be formed, other index plates 95with the numbers of openings desired are attached as required to theadapter block 46.

- The purpose of the dowels 116 (FIG. 3), the recesses 114 in theadapter 47 (FIG. 20), and the recesses 115 in the nozzle blank 30 (FIGS.1 and 2) is not only to hold the nozzle blank 30 against turning in theadapter 47, but also to orient the spray openings 40 with respect to therecesses 114 in the nozzle 30 with respect to the axis thereof. With thespray openings 40 and the recesses 115 oriented with respect to oneanother, the spray openings may be individually oriented about thenozzle axis with respect to an engine (not shown) in which the nozzle 30is applied through dowels (not shown) fitting in the recesses 115 in thenozzle and in recesses (not shown) in the engine.

What is claimed is:

l. A fixture assembly for holding a nozzle blank having a spherical endfor the forming therein of a plurality of spray orifices lying on anddistributed about an imaginary cone having an axis hereinafter calledthe spray-cone axis and an apex angle hereinafter called the spray-coneangle, the orifices being formed by a tool moving along a linehereinafter called the forming axis, said fixture assembly comprising apivot block (45) mounted for angular movement about a first axis (52)perpendicular to the forming axis and containing a second axis (56)angularly movable with the pivot block in a plane perpendicular to thefirst axis and containing the forming axis, a particular angularposition of the pivot block about the-said first axis producing aparticular angle between said second axis and the forming axisdeterminative of a particular spray-cone angle, means for mounting theend of the nozzle blank away from its spherical end on the pivot blockto give the axis (57) of the nozzle blank an angle with said secondaxis, determinative of the angle between the spray-cone axis and saidaxis of the nozzle blank, said mounting means enabling the nozzle blankto be moved about said second axis with respect to the pivot block forthe formation of the various spray orifices of a given plurality thereoflying on the same spray cone, and a headblock (48) having a conicalrecess engageable with the spherical end of the nozzle blank and beingmounted on the pivot block, the conical recess being aligned with saidsecond axis and being intersected by said first axis and said machiningaxis.

2. A fixture assembly for holding a nozzle blank having a spherical endfor the forming therein of a plurality of spray orifices lying on anddistributed about an imaginary cone having an axis hereinafter calledthe spray-cone axis and an angle hereinafter called the spray-coneangle, the orifices being formed by electric-discharge machining by awire moving along a line hereinafter called the machining axis, saidfixture assembly comprising a base, a gage block slidably mounted on thebase and having a series of steps progressively increasing in level fromone step to the next, a pivot block mounted on the base for angularmovement about a first axis perpendicular to the machining axis andcontaining a second axis angularly movable with the pivot block in aplane perpendicular to the first axis and containing the machining axis,the pivot block being engageable with the steps of the gage blockindividually, engagement of the pivot block with a particular step beingproduced by a particular position of the gage block with respect to thebase and producing a particular angular position of the pivot blockabout the said first axis and a particular angle between said secondaxis and the machining axis determinative of a particular spray-coneangle, an adapter block mounted on the pivot block for angular movementwith respect thereto about said second axis and being held againstmovement toward and away from said first axis, an adapter detachablyconnected to the adapter block and adapted to mount the end of thenozzle blank away from its spherical end to give the axis of the nozzleblank an angle with said second axis determinative of the angle betweenthe spray-cone axis and the axis of the nozzle blank, a headblock havinga conical recess in a side facing the adapter and adapter block, andmeans mounting the headblock on the pivot block for adjustment alongsaid second axis, the conical recess being aligned with said second axisand being intersected by said first axis and said machining axis, theconical recess having at one side an opening through which the machiningaxis extends into the conical recess.

3. A fixture assembly, as specified in claim 2, the adapter block beingcircular and cylindrical, said first axis being adjacent one end of thepivot block, the pivot block having a circular cylindrical openingformed in a portion extending from the other end of the pivot block to amid region thereof, the circular cylindrical opening having its axiscoincident with said second axis and receiving and fitting the adapterblock, the adapter being detachably connected with the end of theadapter block toward said first axis, the fixture assembly furthercomprising an index plate detachably connected to the end of the adapteraway from said first axis and extending radially outwardly beyond theadapter so as to overlap said other end of the pivot block, the indexplate having in a region overlapping said other end of the pivot block aplurality of peripherally distributed openings equal in number to theplurality of spray openings to be produced, the fixture assembly furthercomprising a retractable member positioned in said other end of thepivot block so as to be selectively insertable in the openings in theindex plate for fixing the adapter against angular movement about saidsecond axis with respect to the pivot block.

4. A fixture assembly as specified in claim 2, the base comprising afloor and upstanding spaced parallel ears extending upwards therefrom,the gage block being slidable along the floor, the pivot block beingmounted on and between the ears, the pivot block carrying a fixedcylinder engageable with the steps of the gage block.

5. The fixture assembly specified in claim 2 and further comprising anadjusting screw extending through the headblock in threaded engagementtherewith, one end of the screw abutting the pivot block, the other endhaving a large disklike head exterior to the head block and carryingabout its periphery markings indicative of various radii of sphericalends on nozzle blanks to be machined, the adjusting screw beingangularly movable by manual engagement of its head to bring the variousmarkings on the head to a reference marking on the exterior of the headblock radially outward of the head and simultaneously to produce variousamounts of protrusion from the head block of the end of the adjustingscrew abutting the pivot block and consequently various positions of thehead block with respect to the pivot block as well as various spacingsof the conical recess in the head block from the adapter.

6. A fixture assembly as specified in claim 5, each of the pivot blockand the head block having first and second parallel spaced bores, thefirst and second bores of the pivot block being aligned with the firstand second bores of the headblock, respectively, the fixture assemblyfurther comprising a pair of coil springs for maintaining the adjustingscrew in abutment with the pivot block, one spring lying in the firstbores and having one end tied to the pivot block and the other end tiedto the headblock, the other spring lying in the second bores and havingone end tied to the pivot block and the other end tied to the headblock,the fixture assembly further comprising a set screw extending throughthe disklike head of the adjust ing screw in threaded engagementtherewith into abutment with the exterior of the headblock for fixingthe adjusting screw against adjustment.

7. Fixture for vertical drilling of a hole pattern in a nozzle,

comprising:

a rotatable adapter block;

a pivot block with rotatable mounting means rotatably supporting theadapter block thereon, and supported by tiltable mounting means to tiltthe two blocks from a horizontal position about a horizontal pivot axis(52) of the pivot block;

the axis (58) of drilling being perpendicular to the horizontal pivotaxis (52) and intersecting same;

nozzle mounting means on the adapter block for supporting anozzle 30)tobe drilled; said rotata le mounting means effective to rotate theadapter block in the pivot block for rotationally positioning the nozzlefor drilling with a ring of holes a plurality of which are equiangularlyspaced apart;

the axis (56) of rotation of the adapter block being perpendicular tothe horizontal pivot axis (52);

said tiltable mounting means comprising block means engageable at apoint on the pivot block to set the tilt angle by setting the height ofthe pivot block at that point;

said nozzle mounting means comprising adapter means which is revolved bythe adapter block, as the adapter block rotates, to carry the nozzleinto rotational positions as described;

a headblock on the pivot block engageable with the nozzle tip; and

means establishing cooperation to support the headblock on the pivotblock for movement along said axis (56) of rotation and to support theadapter means on the adapter block for movement along said axis (56) ofrotation, for commonly adjusting the nozzle tip linearly into verticalalignment with the axis (58) of drilling aforesaid.

8. The invention of claim 7, the rotatable mounting means characterizedby:

a rotary indexing plate selectable from substitutable indexing platemeans each with a different number of indexed positions affording aprecise number of holes per ring.

9. The invention of claim 7, the tiltable mounting means characterizedby:

a spacer (50) selected from substitutable gage block means each of adifferent measurement determinative of a precise spacing.

10. The invention of claim 7, the nozzle mounting means characterizedby:

an adapter (47) selected from substitutable adapter means each forming adifferent angle to the adapter block determinative of the precise angleof the cone pattern axis to the nozzle axis.

II! i t i

1. A fixture assembly for holding a nozzle blank having a spherical endfor the forming therein of a plurality of spray orifices lying on anddistributed about an imaginary cone having an axis hereinafter calledthe spray-cone axis and an apex angle hereinafter called the spray-coneangle, the orifices being formed by a tool moving along a linehereinafter called the forming axis, said fixture assembly comprising apivot block (45) mounted for angular movement about a first axis (52)perpendicular to the forming axis and containing a second axis (56)angularly movable with the pivot block in a plane perpendicular to thefirst axis and containing the forming axis, a particular angularposition of the pivot block about the said first axis producing aparticular angle between said second axis and the forming axisdeterminative of a particular spray-cone angle, means for mounting theend of the nozzle blank away from its spherical end on the pivot blockto give the axis (57) of the nozzle blank an angle with said secondaxis, determinative of the angle between the spray-cone axis and saidaxis of the nozzle blank, said mounting means enabling the nozzle blankto be movEd about said second axis with respect to the pivot block forthe formation of the various spray orifices of a given plurality thereoflying on the same spray cone, and a headblock (48) having a conicalrecess engageable with the spherical end of the nozzle blank and beingmounted on the pivot block, the conical recess being aligned with saidsecond axis and being intersected by said first axis and said machiningaxis.
 2. A fixture assembly for holding a nozzle blank having aspherical end for the forming therein of a plurality of spray orificeslying on and distributed about an imaginary cone having an axishereinafter called the spray-cone axis and an angle hereinafter calledthe spray-cone angle, the orifices being formed by electric-dischargemachining by a wire moving along a line hereinafter called the machiningaxis, said fixture assembly comprising a base, a gage block slidablymounted on the base and having a series of steps progressivelyincreasing in level from one step to the next, a pivot block mounted onthe base for angular movement about a first axis perpendicular to themachining axis and containing a second axis angularly movable with thepivot block in a plane perpendicular to the first axis and containingthe machining axis, the pivot block being engageable with the steps ofthe gage block individually, engagement of the pivot block with aparticular step being produced by a particular position of the gageblock with respect to the base and producing a particular angularposition of the pivot block about the said first axis and a particularangle between said second axis and the machining axis determinative of aparticular spray-cone angle, an adapter block mounted on the pivot blockfor angular movement with respect thereto about said second axis andbeing held against movement toward and away from said first axis, anadapter detachably connected to the adapter block and adapted to mountthe end of the nozzle blank away from its spherical end to give the axisof the nozzle blank an angle with said second axis determinative of theangle between the spray-cone axis and the axis of the nozzle blank, aheadblock having a conical recess in a side facing the adapter andadapter block, and means mounting the headblock on the pivot block foradjustment along said second axis, the conical recess being aligned withsaid second axis and being intersected by said first axis and saidmachining axis, the conical recess having at one side an opening throughwhich the machining axis extends into the conical recess.
 3. A fixtureassembly, as specified in claim 2, the adapter block being circular andcylindrical, said first axis being adjacent one end of the pivot block,the pivot block having a circular cylindrical opening formed in aportion extending from the other end of the pivot block to a mid regionthereof, the circular cylindrical opening having its axis coincidentwith said second axis and receiving and fitting the adapter block, theadapter being detachably connected with the end of the adapter blocktoward said first axis, the fixture assembly further comprising an indexplate detachably connected to the end of the adapter away from saidfirst axis and extending radially outwardly beyond the adapter so as tooverlap said other end of the pivot block, the index plate having in aregion overlapping said other end of the pivot block a plurality ofperipherally distributed openings equal in number to the plurality ofspray openings to be produced, the fixture assembly further comprising aretractable member positioned in said other end of the pivot block so asto be selectively insertable in the openings in the index plate forfixing the adapter against angular movement about said second axis withrespect to the pivot block.
 4. A fixture assembly as specified in claim2, the base comprising a floor and upstanding spaced parallel earsextending upwards therefrom, the gage block being slidable along thefloor, the pivot block being mounted on and between thE ears, the pivotblock carrying a fixed cylinder engageable with the steps of the gageblock.
 5. The fixture assembly specified in claim 2 and furthercomprising an adjusting screw extending through the headblock inthreaded engagement therewith, one end of the screw abutting the pivotblock, the other end having a large disklike head exterior to the headblock and carrying about its periphery markings indicative of variousradii of spherical ends on nozzle blanks to be machined, the adjustingscrew being angularly movable by manual engagement of its head to bringthe various markings on the head to a reference marking on the exteriorof the head block radially outward of the head and simultaneously toproduce various amounts of protrusion from the head block of the end ofthe adjusting screw abutting the pivot block and consequently variouspositions of the head block with respect to the pivot block as well asvarious spacings of the conical recess in the head block from theadapter.
 6. A fixture assembly as specified in claim 5, each of thepivot block and the head block having first and second parallel spacedbores, the first and second bores of the pivot block being aligned withthe first and second bores of the headblock, respectively, the fixtureassembly further comprising a pair of coil springs for maintaining theadjusting screw in abutment with the pivot block, one spring lying inthe first bores and having one end tied to the pivot block and the otherend tied to the headblock, the other spring lying in the second boresand having one end tied to the pivot block and the other end tied to theheadblock, the fixture assembly further comprising a set screw extendingthrough the disklike head of the adjusting screw in threaded engagementtherewith into abutment with the exterior of the headblock for fixingthe adjusting screw against adjustment.
 7. Fixture for vertical drillingof a hole pattern in a nozzle, comprising: a rotatable adapter block; apivot block with rotatable mounting means rotatably supporting theadapter block thereon, and supported by tiltable mounting means to tiltthe two blocks from a horizontal position about a horizontal pivot axis(52) of the pivot block; the axis (58) of drilling being perpendicularto the horizontal pivot axis (52) and intersecting same; nozzle mountingmeans on the adapter block for supporting a nozzle (30) to be drilled;said rotatable mounting means effective to rotate the adapter block inthe pivot block for rotationally positioning the nozzle for drillingwith a ring of holes a plurality of which are equiangularly spacedapart; the axis (56) of rotation of the adapter block beingperpendicular to the horizontal pivot axis (52); said tiltable mountingmeans comprising block means engageable at a point on the pivot block toset the tilt angle by setting the height of the pivot block at thatpoint; said nozzle mounting means comprising adapter means which isrevolved by the adapter block, as the adapter block rotates, to carrythe nozzle into rotational positions as described; a headblock on thepivot block engageable with the nozzle tip; and means establishingcooperation to support the headblock on the pivot block for movementalong said axis (56) of rotation and to support the adapter means on theadapter block for movement along said axis (56) of rotation, forcommonly adjusting the nozzle tip linearly into vertical alignment withthe axis (58) of drilling aforesaid.
 8. The invention of claim 7, therotatable mounting means characterized by: a rotary indexing plate (95)selectable from substitutable indexing plate means each with a differentnumber of indexed positions affording a precise number of holes perring.
 9. The invention of claim 7, the tiltable mounting meanscharacterized by: a spacer (50) selected from substitutable gage blockmeans each of a different measurement determinative of a precisespacing.
 10. The invention of cLaim 7, the nozzle mounting meanscharacterized by: an adapter (47) selected from substitutable adaptermeans each forming a different angle to the adapter block determinativeof the precise angle of the cone pattern axis to the nozzle axis.